1. Field of the Invention
The present invention relates to a phone conference system and more particularly to an improvement of a phone conference system which interconnects conferences held at a plurality of sites as if the plurality of conferences were being held at only one site.
2. Description of the Prior Art
Due to the developments made in transportation systems, the traveling time between two or more places has been made considerably shorter. The utilization of transportation systems for participating in conferences however, requires time and expense, the amount of time and expense being proportional to the number of people participating in a conference. Therefore, a conference held by people from factories located at different sites involves much expense and loss of time.
In view of this expense and loss of time, there has been a need for the unification of a plurality of conference sites by a telephone switching system. Consequently, a phone conference system in which the drawbacks of conventional phone conference systems are eliminated has recently been developed.
In conventional phone conference systems, the number of microphones and speakers are determined according to the number of participants and the arrangement of each of the conference seats. The number of microphones and speakers are also determined so that a participant's voice can be clearly heard by all of the other participants without the necessity of rearranging the microphones and speakers.
The number of participants differs in accordance with the content of the conference, with the result that the required number of speakers and microphones differs depending on the type of conference. Therefore, the capacity suitable for common amplifiers for the transmitter-receiver and the number of circuits used in mixers also differ.
Usually, at each conference site, the conference system is formed with a suitable scale of equipment in accordance with the number of participants so that various conference systems providing a predetermined number of microphones and speakers are provided.
Consequently, if the scale of the conference is determined in accordance with the maximum number of participants, a phone conference system is usually uneconomical.